//
// Created by wze-zero on 2024/10/27.
//
#include <iostream>

using namespace std;

long long factorial(int n);

int main() {
    int n;
    cin >> n;
    cout << factorial(n) << endl;
    return 0;
}

long long factorial(int n) {
    if (n == 1) {
        return 1;
    } else {
        return n * factorial(n - 1);
    }
}